97 z 24 idles high and shifts late. happened overnight?

my 97 z 24 ran fine when i parked. in the morning when i started it it was idling high. i put it in reverse and it slammed into gear. when i started driving it wont shift until i let of the gas at about 4000 rpm any ideas im stumped.

Sounds like it might be a significant vacuum leak. That can be from a hose, gasket, PDV, EGR, brake booster, or any of a number of other possibilities.